### Note this is my personal todo and ideas list, don't jump on me if you don't like something or think that it isn't important enough. * linuxulator - get ltp working - update it part by part! * kbd - port this: http://svn.freebsd.org/viewvc/base/head/sys/dev/kbd/kbd.c?revision=112050&view=markup - remove kbd_reinit_struct - unicode? - remove need for mplock * sync syscons as far as possible - tty changes not possible... * port wscons (?) - probably way too much effort. * port the mpsafe tty stuff from FreeBSD - or mpsafe ours. - http://svn.freebsd.org/viewvc/base?view=revision&revision=181905 and quite a few later ones - http://p4db.freebsd.org/changeList.cgi?FSPC=%2F%2Fdepot%2Fprojects%2Fmpsafetty%2F...&ignore=GO%21 - all related drivers, listed in UPDATING in the above revision, and others - DON'T port pts driver, rather stick to ours but modify it to work with new ttys - http://svn.freebsd.org/viewvc/base/head/sys/dev/snp/snp.c?view=log - http://svn.freebsd.org/viewvc/base/head/sys/dev/si/si.c?view=log * port usb4bsd - wrapper is included for userland; should be easy to port - http://svn.freebsd.org/viewvc/base?view=revision&revision=184610 - http://turbocat.net/~hselasky/usb4bsd/ * sync up vr o Added VT6105M specific register definitions. VT6105M has the following hardware capabilities. - Tx/Rx IP/TCP/UDP checksum offload. - VLAN hardware tag insertion/extraction. Due to lack of information for getting extracted VLAN tag in Rx path, VLAN hardware support was not implemented yet. - CAM(Content Addressable Memory) based 32 entry perfect multicast/ VLAN filtering. - 8 priority queues. o Implemented CAM based 32 entry perfect multicast filtering for VT6105M. If number of multicast entry is greater than 32, vr(4) uses traditional hash based filtering. * do something similar to geom (maybe with compat layer for geom?) - http://svn.freebsd.org/viewvc/base?view=revision&revision=92108 - while here, "layerize" the disk subsystem * continue work on disk scheduler - focus on initial fair queueing policy as proof of concept - see branch. * ATA (automatic) spindown (see FreeBSD current) * The ata(4) driver now supports a loader variable hw.ata.ata_dma_check_80pin. - This can be used to disable the 80pin cable check on broken systems such as certain laptops and Soekris boards. The default value is 1. * RedZone, a buffer corruption protection for the kernel malloc(9) facility has been implemented. - This detects both buffer underflows and overflows at runtime on free(9) and realloc(9), and prints backtraces from where memory was allocated and from where it was freed. - see irc log below. * port uart driver (?) * simplify/improve i386 - http://svn.freebsd.org/viewvc/base?view=revision&revision=173592 - http://svn.freebsd.org/viewvc/base/head/sys/i386/i386/i686_mem.c?view=log - http://svn.freebsd.org/viewvc/base/head/sys/i386/i386/initcpu.c?view=log - http://svn.freebsd.org/viewvc/base/head/sys/i386/i386/pmap.c?view=log - http://svn.freebsd.org/viewvc/base/head/sys/i386/i386/locore.s?view=log * suspend/resume for SMP x86 - http://lists.freebsd.org/pipermail/freebsd-acpi/2008-May/004879.html * route show * AMD64 suspend/resume - http://svn.freebsd.org/viewvc/base?view=revision&revision=189903 * code simplification (Introduce cpu_vendor_id and replace a lot of strcmp(cpu_vendor, "...") - http://svn.freebsd.org/viewvc/base?view=revision&revision=185341 * APIC stuff - http://svn.freebsd.org/viewvc/base/head/sys/i386/i386/mptable.c?view=log - http://svn.freebsd.org/viewvc/base/head/sys/i386/i386/mptable_pci.c?view=log - http://svn.freebsd.org/viewvc/base/head/sys/i386/i386/io_apic.c?view=log - MOST IMPORTANTLY: http://svn.freebsd.org/viewvc/base?view=revision&revision=121986 - AND: http://svn.freebsd.org/viewvc/base?view=revision&revision=121991 * crash analysis tool - http://svn.freebsd.org/viewvc/base?view=revision&revision=181335 * utmpx - CFLAGS="-DUTMPX_USE_LIBRARY -DHAVE_UTMPX_H -DUSE_UTMPX" - see branch, but still missing update to pam! (proper update) * Update callout http://svn.freebsd.org/viewvc/base?view=revision&revision=127969 * unionfs update - use namecache tricks as nullfs does - make it work without whiteout * inv ctxsw rusage - see irc logs * synchronization routines documentation page (compare all the following, highlight differences) - mtx - spinlock - lockmgr - critical section - lwkt serialization tokens - lwkt messages devclass_find_internal(const char *classname, const char *parentname, 543 int create) [alexh@leaf:~/home] $ roundup-server -p 8080 bt=bugtracker
-05:48- : dillon@: no, double frees to the object cache are nasty. It can't detect them. the object winds up in the magazine array twice -05:48- : dillon@: (and possibly different magazines, too) -05:49- : alexh@: can't I just write some magic to a free object on the first objcache_put and check if it's there on objcache_put? -05:49- : alexh@: and clear it on objcache_get, anyways -05:50- : dillon@: no, because the object is still may have live-initialized fields -05:50- : dillon@: because it hasn't been dtor'ed yet (one of the features of the objcache, to avoid having to reinitialize objects every time) -05:50- : dillon@: the mbuf code uses that feature I think, probably other bits too -05:51- : dillon@: theoretically we could allocate slightly larger objects and store a magic number at offset [-1] or something like that, but it gets a little iffy doing that -05:52- : dillon@: the objcache with the objcache malloc default could probably do something like that I guess. -05:52- : dillon@: I don't consider memory tracking to be a huge issue w/ dragonfly, though I like the idea of being able to do it. It is a much bigger problem in FreeBSD due to the large number of committers -05:55- : dillon@: For the slab allocator you may be able to do something using the Zone header. -05:55- : dillon@: the slab allocator in fact I think already has optional code to allocate a tracking bitmap to detect double-frees -05:56- : dillon@: sorry, I just remembered the bit about the power-of-2 allocations -05:56- : dillon@: for example, power-of-2-sized allocations are guaranteed not only to be aligned on that particular size boundary, but also to not cross a PAGE_BOUNDARY (unless the size is > PAGE_SIZE) -05:57- : dillon@: various subsystems such as AHCI depend on that behavior to allocate system structures for which the chipsets only allow one DMA descriptor. -05:59- : alexh@: http://svn.freebsd.org/viewvc/base/head/sys/vm/redzone.c?view=markup&pathrev=155086 < this is redzone. it basically calls redzone_addr_ntor() to increase the size in malloc(), and then redzone_setup() just before returning the chunk -06:02- : dillon@: jeeze. that looks horrible. -06:03- : alexh@: I don't quite get that nsize + redzone_roundup(nsize) -06:03- : dillon@: I don't get it either. It would completely break power-of-2-sized alignments in the original request -06:04- : dillon@: hmmm. well, no it won't break them, but the results are oging to be weird -06:04- : dillon@: ick. -06:15- : dillon@: if the original request is a power of 2 the redzone adjusted request must be a power of 2 -06:15- : dillon@: basically -06:16- : dillon@: so original request 64, redzone request must be 128, 256, 512, 1024, etc. -06:16- : alexh@: yah, k -06:16- : dillon@: original request 32, current redzone code would be 32+128 which is WRONG. -06:16- : alexh@: how big is PAGE_SIZE ? -06:16- : dillon@: 4096 on i386 and amd64 -06:17- : alexh@: and one single malloc can't be bigger than that? -06:17- : dillon@: I'm fairly sure our kmalloc does not guarantee alignment past PAGE_SIZE (that is, the alignment will be only PAGE_SIZE eve if you allocate PAGE_SIZE*2) -06:17- : dillon@: a single kmalloc can be larger then PAGE_SIZe -06:18- : dillon@: it will use the zone up to around 1/2 the zone size (~64KB I think), after which it allocates pages directly with the kernel kvm allocator -06:18- : dillon@: if you look at the kmalloc code you will see the check for oversized allocations -06:18- : alexh@: yah, saw that -06:18- : alexh@: "handle large allocations directly" -06:19- : alexh@: not sure how to do this, really, as the size is obviously also changed in kmem_slab_alloc -06:20- : alexh@: but kmem_slab_alloc isn't called always, is it? -06:20- : alexh@: only if the req doesn't fit into an existant zone -06:20- : dillon@: right -06:20- : dillon@: you don't want to redzone the zone allocation itself